Method and apparatus for producing flexible oled device

ABSTRACT

According to a flexible OLED device production method of the present disclosure, after an intermediate region ( 30   i ) and flexible substrate regions ( 30   d ) of a plastic film ( 30 ) of a multilayer stack ( 100 ) are divided from one another, the interface between the flexible substrate regions ( 30   d ) and a glass base ( 10 ) is irradiated with laser light. The multilayer stack ( 100 ) is separated into a first portion ( 110 ) and a second portion ( 120 ) while the multilayer stack ( 100 ) is in contact with a stage ( 212 ). The first portion ( 110 ) includes a plurality of OLED devices ( 1000 ) which are in contact with the stage ( 212 ). The OLED devices ( 1000 ) include a plurality of functional layer regions ( 20 ) and the flexible substrate regions ( 30   d ). The second portion ( 120 ) includes the glass base ( 10 ) and the intermediate region ( 30   i ).

TECHNICAL FIELD

The present disclosure relates to a method and apparatus for producing aflexible OLED device.

BACKGROUND ART

A typical example of the flexible display includes a film which is madeof a synthetic resin such as polyimide (hereinafter, referred to as“plastic film”), and elements supported by the plastic film, such asTFTs (Thin Film Transistors) and OLEDs (Organic Light Emitting Diodes).The plastic film functions as a flexible substrate. The flexible displayis encapsulated with a gas barrier film (encapsulation film) because anorganic semiconductor layer which is a constituent of the OLED is likelyto deteriorate due to water vapor.

Production of the above-described flexible display is carried out usinga glass base on which a plastic film is formed over the upper surface.The glass base functions as a support (carrier) for keeping the shape ofthe plastic film flat during the production process. Elements such asTFTs and OLEDs, a gas barrier film, and the other constituents areformed on the plastic film, whereby the structure of a flexible OLEDdevice is realized while it is supported by the glass base. Thereafter,the flexible OLED device is delaminated from the glass base and gainsflexibility. The entirety of a portion in which elements such as TFTsand OLEDs are arrayed can be referred to as “functional layer region”.

According to the prior art, a sheet-like structure including a pluralityof flexible OLED devices is delaminated from a glass base, andthereafter, optical parts and other constituents are mounted to thissheet-like structure. Thereafter, the sheet-like structure is dividedinto a plurality of flexible devices. This dividing is realized by, forexample, laser beam irradiation.

Patent Document No. 1 discloses the method of irradiating the interfacebetween each flexible OLED device and the glass base with laser light(lift-off light) in order to strip each flexible OLED device from theglass base (supporting substrate). According to the method disclosed inPatent Document No. 1, after irradiation with the lift-off light,respective flexible OLED devices are divided from one another, and eachof the flexible OLED devices is delaminated from the glass base.

CITATION LIST Patent Literature

Patent Document No. 1: Japanese Laid-Open Patent Publication No.2014-48619

SUMMARY OF INVENTION Technical Problem

According to the conventional production method, the dividing by meansof laser beam irradiation is carried out after expensive parts, forexample, encapsulation film, polarizer, and/or heat radiation sheet, aremounted to a sheet-like structure including a plurality of flexible OLEDdevices. Therefore, unnecessary parts divided by laser beam irradiation,i.e., parts which are not to be constituents of a final OLED device, arequite useless. Also, there is a problem that, after being delaminatedfrom the glass base, it is difficult to handle a plurality of flexibleOLED devices which have no rigidity.

The present disclosure provides a method and apparatus for producing aflexible OLED device which are capable of solving the above-describedproblems.

Solution to Problem

A flexible OLED device production method of the present disclosureincludes, in an exemplary embodiment, providing a multilayer stack whichhas a first surface and a second surface, the multilayer stack includinga glass base which defines the first surface, a plurality of functionallayer regions each including a TFT layer and an OLED layer, a syntheticresin film provided between the glass base and the plurality offunctional layer regions and bound to the glass base, the syntheticresin film including a plurality of flexible substrate regionsrespectively supporting the plurality of functional layer regions and anintermediate region surrounding the plurality of flexible substrateregions, and a protection sheet which covers the plurality of functionallayer regions and which defines the second surface; dividing theintermediate region and respective ones of the plurality of flexiblesubstrate regions of the synthetic resin film from one another;irradiating an interface between the plurality of flexible substrateregions of the synthetic resin film and the glass base with laser light;and separating the multilayer stack into a first portion and a secondportion by increasing a distance from a stage to the glass base whilethe second surface of the multilayer stack is kept in contact with thestage. The first portion of the multilayer stack includes a plurality ofOLED devices which are in contact with the stage, and the plurality ofOLED devices respectively include the plurality of functional layerregions and include the plurality of flexible substrate regions of thesynthetic resin film, and the second portion of the multilayer stackincludes the glass base and the intermediate region of the syntheticresin film.

In one embodiment, separating the multilayer stack into the firstportion and the second portion is carried out while the stage holds thesecond surface of the multilayer stack.

In one embodiment, irradiating the interface between the plurality offlexible substrate regions of the synthetic resin film and the glassbase with the laser light is carried out while the stage holds thesecond surface of the multilayer stack.

In one embodiment, a surface of the stage includes a first region whichis to face the plurality of OLED devices and a second region which is toface the intermediate region of the synthetic resin film, and suction inthe first region is greater than suction in the second region.

In one embodiment, the method further includes, before bringing thesecond surface of the multilayer stack into contact with the stage,placing a suction sheet on the stage, the suction sheet having aplurality of openings, wherein the stage includes a porous plate onwhich the suction sheet is to be placed, and the suction sheet includesa first region which is to be in contact with the plurality of OLEDdevices and a second region which is to face the intermediate region ofthe synthetic resin film, an aperture ratio of the first region beinghigher than an aperture ratio of the second region.

In one embodiment, the method further includes, after separating themultilayer stack into the first portion and the second portion,sequentially or concurrently performing a process on the plurality ofOLED devices which are in contact with the stage.

In one embodiment, the method further includes, after separating themultilayer stack into the first portion and the second portion, adheringanother protection sheet to the plurality of OLED devices which are incontact with the stage.

In one embodiment, the method further includes detaching from the stagethe plurality of OLED devices which are bound to the another protectionsheet.

In one embodiment, the method further includes sequentially orconcurrently performing a process on the plurality of OLED devices whichare bound to the another protection sheet.

In one embodiment, the process includes attaching a dielectric and/orelectrically-conductive film to each of the plurality of OLED devices.

In one embodiment, the process includes cleaning or etching each of theplurality of OLED devices.

In one embodiment, the process includes mounting an optical part and/oran electronic part to each of the plurality of OLED devices.

In one embodiment, the process includes cleaning or etching each of theplurality of OLED devices.

A flexible OLED device production apparatus of the present disclosureincludes, in an exemplary embodiment, a stage for supporting amultilayer stack which has a first surface and a second surface, themultilayer stack including a glass base which defines the first surface,a plurality of functional layer regions each including a TFT layer andan OLED layer, a synthetic resin film provided between the glass baseand the plurality of functional layer regions and bound to the glassbase, the synthetic resin film including a plurality of flexiblesubstrate regions respectively supporting the plurality of functionallayer regions and an intermediate region surrounding the plurality offlexible substrate regions, and a protection sheet which covers theplurality of functional layer regions and which defines the secondsurface, the intermediate region and respective ones of the plurality offlexible substrate regions of the synthetic resin film being dividedfrom one another; a lift-off light irradiation unit for irradiating withlaser light an interface between the plurality of flexible substrateregions of the synthetic resin film and the glass base in the multilayerstack supported by the stage; and an actuator for increasing a distancefrom the stage to the glass base while the stage holds the secondsurface of the multilayer stack by suction, thereby separating themultilayer stack into a first portion and a second portion. The firstportion of the multilayer stack includes a plurality of OLED devicesadhered by suction to the stage, and the plurality of OLED devicesrespectively include the plurality of functional layer regions andinclude the plurality of flexible substrate regions of the syntheticresin film, and the second portion of the multilayer stack includes theglass base and the intermediate region of the synthetic resin film.

In one embodiment, the surface of the stage includes a first regionwhich is to face the plurality of OLED devices and a second region whichis to face the intermediate region of the synthetic resin film, andsuction in the first region is greater than suction in the secondregion.

In one embodiment, the stage includes a porous plate, and a suctionsheet placed on the porous plate, the suction sheet having a pluralityof openings, and the suction sheet includes a first region which is tobe in contact with the plurality of OLED devices and a second regionwhich is to face the intermediate region of the synthetic resin film, anaperture ratio of the first region being higher than an aperture ratioof the second region.

A suction sheet of the present disclosure is, in an exemplaryembodiment, a suction sheet for use in the above-described productionapparatus, the suction sheet including: a first region which is to be incontact with the plurality of OLED devices; and a second region which isto face the intermediate region of the synthetic resin film, wherein anaperture ratio of the first region is higher than an aperture ratio ofthe second region.

Advantageous Effects of Invention

According to an embodiment of the present invention, a novel method forproducing a flexible OLED device which is capable of solving theabove-described problems is provided.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is a plan view showing a configuration example of a multilayerstack used in a flexible OLED device production method of the presentdisclosure.

FIG. 1B is a cross-sectional view of the multilayer stack taken alongline B-B of FIG. 1A.

FIG. 1C is a cross-sectional view showing another example of themultilayer stack.

FIG. 1D is a cross-sectional view showing still another example of themultilayer stack.

FIG. 2 is a cross-sectional view schematically showing the dividingpositions in the multilayer stack.

FIG. 3A is a diagram schematically showing a state immediately before astage supports a multilayer stack.

FIG. 3B is a diagram schematically showing a state where the stagesupports the multilayer stack.

FIG. 3C is a diagram schematically showing that the interface between aglass base and a plastic film of the multilayer stack with laser light(lift-off light) in the shape of a line.

FIG. 4A is a perspective view schematically showing irradiation of themultilayer stack with a line beam emitted from a line beam source of adelaminating apparatus.

FIG. 4B is a diagram schematically showing the position of the stage atthe start of irradiation with lift-off light.

FIG. 4C is a diagram schematically showing the position of the stage atthe end of irradiation with lift-off light.

FIG. 5A is a cross-sectional view schematically showing the multilayerstack before the multilayer stack is separated into the first portionand the second portion after irradiation with lift-off light.

FIG. 5B is a cross-sectional view schematically showing the multilayerstack separated into the first portion and the second portion.

FIG. 6 is a perspective view showing the glass base separated from themultilayer stack by the delaminating apparatus.

FIG. 7 is a perspective view schematically showing a surface of thestage.

FIG. 8 is a plan view schematically showing the surface of the stage.

FIG. 9A is a schematic diagram enlargedly showing a portion in thevicinity of the boundary between a first region and a second region ofthe surface in a configuration example of the stage.

FIG. 9B is a cross-sectional view taken along line B-B of FIG. 9A.

FIG. 10 is a plan view showing the surface in another configurationexample of the stage.

FIG. 11A is a schematic diagram enlargedly showing a portion in thevicinity of the boundary between a first region and a second region ofthe surface in still another configuration example of the stage.

FIG. 11B is a cross-sectional view taken along line B-B of FIG. 11A.

FIG. 12A is a schematic diagram enlargedly showing a portion in thevicinity of the boundary between a first region and a second region ofthe surface in another configuration example of the stage.

FIG. 12B is a cross-sectional view taken along line B-B of FIG. 12A.

FIG. 13 is a perspective view showing removal of the glass base from thestage.

FIG. 14 is a perspective view showing the stage from which the glassbase has been removed.

FIG. 15 is a cross-sectional view showing the stage from which the glassbase has been removed.

FIG. 16 is a cross-sectional view showing flexible OLED devices detachedfrom the stage.

FIG. 17 is a cross-sectional view showing another protection sheet boundto a plurality of OLED devices which are in contact with the stage.

FIG. 18 is a cross-sectional view showing a carrier sheet carrying aplurality of parts which are to be mounted to the plurality of OLEDdevices.

FIG. 19A is a cross-sectional view illustrating a step of the flexibleOLED device production method in an embodiment of the presentdisclosure.

FIG. 19B is a cross-sectional view illustrating a step of the flexibleOLED device production method in an embodiment of the presentdisclosure.

FIG. 19C is a cross-sectional view illustrating a step of the flexibleOLED device production method in an embodiment of the presentdisclosure.

FIG. 19D is a cross-sectional view illustrating a step of the flexibleOLED device production method in an embodiment of the presentdisclosure.

FIG. 20 is an equivalent circuit diagram of a single sub-pixel in aflexible OLED device.

FIG. 21 is a perspective view of the multilayer stack in the middle ofthe production process.

DESCRIPTION OF EMBODIMENTS

An embodiment of a method and apparatus for producing a flexible OLEDdevice of the present disclosure is described with reference to thedrawings. In the following description, unnecessarily detaileddescription will be omitted. For example, detailed description ofwell-known matter and repetitive description of substantially identicalelements will be omitted. This is for the purpose of avoiding thefollowing description from being unnecessarily redundant and assistingthose skilled in the art to easily understand the description. Thepresent inventors provide the attached drawings and the followingdescription for the purpose of assisting those skilled in the art tofully understand the present disclosure. Providing these drawings anddescription does not intend to limit the subject matter recited in theclaims.

<Multilayer Stack>

See FIG. 1A and FIG. 1B. In a flexible OLED device production method ofthe present embodiment, firstly, a multilayer stack 100 illustrated inFIG. 1A and FIG. 1B is provided. FIG. 1A is a plan view of themultilayer stack 100. FIG. 1B is a cross-sectional view of themultilayer stack 100 taken along line B-B of FIG. 1A. In FIG. 1A andFIG. 1B, an XYZ coordinate system with X-axis, Y-axis and Z-axis, whichare perpendicular to one another, is shown for reference.

The multilayer stack 100 includes a glass base (motherboard or carrier)10, a plurality of functional layer regions 20 each including a TFTlayer 20A and an OLED layer 20B, a synthetic resin film (hereinafter,simply referred to as “plastic film”) 30 provided between the glass base10 and the plurality of functional layer regions 20 and bound to theglass base 10, and a protection sheet 50 covering the plurality offunctional layer regions 20. The multilayer stack 100 further includes agas barrier film 40 provided between the plurality of functional layerregions 20 and the protection sheet 50 so as to cover the entirety ofthe functional layer regions 20. The multilayer stack 100 may includeanother unshown layer, such as a buffer layer.

The first surface 100 a of the multilayer stack 100 is defined by theglass base 10. The second surface 100 b of the multilayer stack 100 isdefined by the protection sheet 50. The glass base 10 and the protectionsheet 50 are materials temporarily used in the production process butare not constituents of a final flexible OLED device.

The plastic film 30 shown in the drawings includes a plurality offlexible substrate regions 30 d respectively supporting the plurality offunctional layer regions 20, and an intermediate region 30 i surroundingeach of the flexible substrate regions 30 d. The flexible substrateregions 30 d and the intermediate region 30 i are merely differentportions of a single continuous plastic film 30 and do not need to bephysically distinguished. In other words, parts of the plastic film 30lying immediately under respective ones of the functional layer regions20 are the flexible substrate regions 30 d, and the other part of theplastic film 30 is the intermediate region 30 i.

Each of the plurality of functional layer regions 20 is a constituent ofa final flexible OLED device. In other words, the multilayer stack 100has such a structure that a plurality of flexible OLED devices which arenot yet divided from one another are supported by a single glass base10. Each of the functional layer regions 20 has such a shape that, forexample, the thickness (size in Z-axis direction) is several tens ofmicrometers, the length (size in X-axis direction) is about 12 cm, andthe width (size in Y-axis direction) is about 7 cm. These sizes can beset to arbitrary values according to the required largeness of thedisplay screen. The shape in the XY plane of each of the functionallayer regions 20 is rectangular in the example illustrated in thedrawings but is not limited to this example. The shape in the XY planeof each of the functional layer regions 20 may include a square, apolygon, or a shape which includes a curve in the contour.

As shown in FIG. 1A, the flexible substrate regions 30 d aretwo-dimensionally arrayed in rows and columns according to thearrangement of the flexible OLED devices. The intermediate region 30 iconsists of a plurality of stripes perpendicular to one another andforms a grid pattern. The width of the stripes is, for example, about1-4 mm. The flexible substrate region 30 d of the plastic film 30functions as the “flexible substrate” in each flexible OLED device whichis in the form of a final product. Meanwhile, the intermediate region 30i of the plastic film 30 is not a constituent of the final product.

In an embodiment of the present disclosure, the configuration of themultilayer stack 100 is not limited to the example illustrated in thedrawings. The number of functional layer regions 20 supported by asingle glass base 10 is arbitrary.

The size or proportion of each component illustrated in respectivedrawings is determined from the viewpoint of understandability. Theactual size or proportion is not necessarily reflected in the drawings.

The multilayer stack 100 which can be used in the production method ofthe present disclosure is not limited to the example illustrated in FIG.1A and FIG. 1B. FIG. 1C and FIG. 1D are cross-sectional views showingother examples of the multilayer stack 100. In the example illustratedFIG. 1C, the protection sheet 50 covers the entirety of the plastic film30 and extends outward beyond the plastic film 30. In the exampleillustrated FIG. 1D, the protection sheet 50 covers the entirety of theplastic film 30 and extends outward beyond the glass base 10. As will bedescribed later, after the glass base 10 is separated from themultilayer stack 100, the multilayer stack 100 is a thin flexiblesheet-like structure which has no rigidity. The protection sheet 50serves to protect the functional layer regions 20 from impact andabrasion when the functional layer regions 20 collide with or come intocontact with external apparatuses or instruments in the step ofdelaminating the glass base 10 and the steps after the delaminating.Since the protection sheet 50 is peeled off from the multilayer stack100 in the end, a typical example of the protection sheet 50 has alaminate structure which includes an adhesive layer of a relativelysmall adhesive force (a layer of an applied mold-releasing agent) overits surface. The more detailed description of the multilayer stack 100will be described later.

<Dividing of OLED Devices>

According to the flexible OLED device production method of the presentembodiment, after the step of providing the above-described multilayerstack 100, the step of dividing an intermediate region 30 i andrespective ones of a plurality of flexible substrate regions 30 d of theplastic film 30 from one another is carried out.

FIG. 2 is a cross-sectional view schematically showing the positions fordividing the intermediate region 30 i and respective ones of theplurality of flexible substrate regions 30 d of the plastic film 30 fromone another. The positions of irradiation extend along the periphery ofeach of the flexible substrate regions 30 d. In FIG. 2, the positionsindicated by arrows are irradiated with a laser beam for cutting. Partof the multilayer stack 100 exclusive of the glass base 10 is cut into aplurality of OLED devices 1000 and the remaining unnecessary portions.By cutting, a gap of several tens of micrometers to several hundreds ofmicrometers is formed between each of the OLED devices 1000 and aportion surrounding the OLED device 1000. The cutting can also berealized by a dicing saw instead of the laser beam irradiation. Afterthe cutting, the OLED devices 1000 and the remaining unnecessaryportions are still bound to the glass base 10.

When the cutting is realized by a laser beam, the wavelength of thelaser beam may be in any of the infrared, visible and ultraviolet bands.From the viewpoint of reducing the effect of the cutting on the glassbase 10, the laser beam desirably has a wavelength in the range of greento ultraviolet. For example, when a Nd:YAG laser device is used, thecutting can be carried out using a second harmonic wave (wavelength: 532nm) or a third harmonic wave (wavelength: 343 nm or 355 nm). In such acase, the laser power is adjusted to 1 to 3 watts, and the scanning rateis set to about 500 mm per second, so that the multilayer structuresupported by the glass base 10 can be cut (divided) into OLED devicesand unnecessary portions without damaging the glass base 10.

According to the embodiment of the present disclosure, the timing of theabove-described cutting is earlier than in the prior art. Since thecutting is carried out while the plastic film 30 is bound to the glassbase 10, alignment for the cutting can be made with high precision andaccuracy even if the gap between adjoining OLED devices 1000 is narrow.Thus, the gap between adjoining OLED devices 1000 can be shortened, andaccordingly, useless portions which are unnecessary for a final productcan be reduced. In the prior art, after the delaminating from the glassbase 10, a polarizer, a heat radiation sheet, and/or an electromagneticshield can be adhered to the plastic film 30 so as to cover the entiretyof the surface (delaminated surface) of the plastic film 30. In such acase, the polarizer, the heat radiation sheet, and/or theelectromagnetic shield are also divided by cutting into portionscovering the OLED devices 1000 and the remaining unnecessary portions.The unnecessary portions are disposed of as waste. On the other hand,according to the production method of the present disclosure, productionof such waste can be suppressed as will be described later.

<Lift-Off Light Irradiation>

After the intermediate region 30 i and respective ones of the pluralityof flexible substrate regions 30 d of the plastic film 30 are dividedfrom one another, the step of irradiating the interface between theflexible substrate regions 30 d of the plastic film 30 and the glassbase 10 with laser light is carried out using a delaminating apparatus.

FIG. 3A schematically shows a state in an unshown production apparatus(delaminating apparatus) immediately before the stage 212 supports themultilayer stack 100. In the present embodiment, the stage 212 is achuck stage which has a large number of pores in the surface forsuction. Details of the configuration of the chuck stage will bedescribed later. The multilayer stack 100 is arranges such that thesecond surface 100 b of the multilayer stack 100 faces the surface 212Sof the stage 212, and is supported by the stage 212.

FIG. 3B schematically shows a state where the stage 212 supports themultilayer stack 100. The arrangement of the stage 212 and themultilayer stack 100 is not limited to the example illustrated in thedrawing. For example, the multilayer stack 100 may be placed upside downsuch that the stage 212 is present under the multilayer stack 100.

In the example illustrated in FIG. 3B, the multilayer stack 100 is incontact with the surface 212S of the stage 212, and the stage 212 holdsthe multilayer stack 100 by suction.

Then, as shown in FIG. 3C, the interface between the plurality offlexible substrate regions 30 d of the plastic film 30 and the glassbase 10 is irradiated with laser light (lift-off light) 216. FIG. 3Cschematically illustrates irradiation of the interface between the glassbase 10 and the plastic film 30 of the multilayer stack 100 with thelift-off light 216 in the shape of a line extending in a directionvertical to the sheet of the drawing. A part of the plastic film 30 atthe interface between the glass base 10 and the plastic film 30 absorbsthe lift-off light 216 and decomposes (disappears). By scanning theabove-described interface with the lift-off light 216, the degree ofbinding of the plastic film 30 to the glass base 10 is reduced. Thewavelength of the lift-off light 216 is typically in the ultravioletband. The wavelength of the lift-off light 216 is selected such that thelift-off light 216 is hardly absorbed by the glass base 10 but isabsorbed by the plastic film 30 as much as possible. The lightabsorption by the glass base 10 is, for example, about 10% in thewavelength range of 343-355 nm but can increase to 30-60% at 308 nm.

In the present embodiment, the delaminating apparatus includes a linebeam source for emitting the lift-off light 216. The line beam sourceincludes a laser device and an optical system for shaping laser lightemitted from the laser device into a line beam.

FIG. 4A is a perspective view schematically showing irradiation of themultilayer stack 100 with a line beam (lift-off light 216) emitted froma line beam source 214 of a delaminating apparatus 220. For the sake ofunderstandability, the stage 212, the multilayer stack 100 and the linebeam source 214 are shown as being spaced away from one another in theZ-axis direction of the drawing. During irradiation with the lift-offlight 216, the second surface 100 b of the multilayer stack 100 is incontact with the stage 212.

FIG. 4B schematically shows the position of the stage 212 duringirradiation with the lift-off light 216. Although not shown in FIG. 4B,the multilayer stack 100 is supported by the stage 212.

Examples of the laser device that emits the lift-off light 216 includegas laser devices such as excimer laser, solid laser devices such as YAGlaser, semiconductor laser devices, and other types of laser devices. AXeCl excimer laser device can generate laser light at the wavelength of308 nm. When yttrium orthovanadate (YVO₄) doped with neodymium (Nd) orYVO₄ doped with ytterbium (Yb) is used as a lasing medium, thewavelength of laser light (fundamental wave) emitted from the lasingmedium is about 1000 nm. Therefore, the fundamental wave can beconverted by a wavelength converter to laser light at the wavelength of340-360 nm (third harmonic wave) before it is used.

A sacrificial layer (a thin layer of a metal or amorphous silicon) maybe provided at the interface between the plastic film 30 and the glassbase 10. From the viewpoint of suppressing generation of ashes, usinglaser light at the wavelength of 308 nm from the excimer laser device,rather than laser light at the wavelength of 340-360 nm, is moreeffective. Providing the sacrificial layer is highly effective insuppressing generation of ashes.

The irradiation with the lift-off light 216 can be carried out with thepower density (irradiance) of, for example, 250-300 mJ/cm². The lift-offlight 216 in the shape of a line beam has a size which can extend acrossthe glass base 10, i.e., a line length which exceeds the length of oneside of the glass base (long axis dimension, size in Y-axis direction ofFIG. 4B). The line length can be, for example, not less than 750 mm.Meanwhile, the line width of the lift-off light 216 (short axisdimension, size in X-axis direction of FIG. 4B) can be, for example,about 0.2 mm. These dimensions represent the size of the irradiationregion at the interface between the plastic film 30 and the glass base10. The lift-off light 216 can be emitted in the form of a pulsed orcontinuous wave. Irradiation with the pulsed wave can be carried out atthe frequency of, for example, about 200 times per seconds.

The position of irradiation with the lift-off light 216 moves relativeto the glass base 10 for scanning with the lift-off light 216. In thedelaminating apparatus 220, the multilayer stack 100 may be movablewhile the light source 214 from which the lift-off light is to beemitted and an optical unit (not shown) are stationary, and vice versa.In the present embodiment, irradiation with the lift-off light 216 iscarried out during a period where the stage 212 moves from the positionshown in FIG. 4B to the position shown in FIG. 4C. That is, scanningwith the lift-off light 216 is carried out by movement of the stage 212in the X-axis direction.

<Lift-Off>

FIG. 5A illustrates a state where the multilayer stack 100 is in contactwith the stage 212 after irradiation with the lift-off light. While thisstate is maintained, the distance from the stage 212 to the glass base10 is increased. At this point in time, the stage 212 of the presentembodiment holds an OLED device portion of the multilayer stack 100. Atthis point in time, a part of the intermediate region 30 i located at anend of the plastic film 30 may be secured to the glass base 10 using anunshown pin or jig. The securing positions can be, for example, at thefour corners of the plastic film 30.

An actuator holds the glass base 10 and moves the entirety of the glassbase 10 in the direction of arrow L, thereby carrying out delaminating(lift-off). The glass base 10 can be moved together with an unshownchuck stage while being adhered by suction to the chuck stage. Thedirection of movement of the glass base 10 does not need to be vertical,but may be diagonal, to the first surface 100 a of the multilayer stack100. The movement of the glass base 10 does not need to be linear butmay be rotational. Alternatively, the stage 212 may be moved upward inthe drawing while the glass base 10 is secured by an unshown holder oranother stage.

FIG. 5B is a cross-sectional view showing the thus-separated firstportion 110 and second portion 120 of the multilayer stack 100. FIG. 6is a perspective view showing the second portion 120 of the multilayerstack 100. The first portion 110 of the multilayer stack 100 includes aplurality of OLED devices 1000 which are in contact with the stage 212.The respective OLED devices 1000 include the functional layer regions 20and the plurality of flexible substrate regions 30 d of the plastic film30. Meanwhile, the second portion 120 of the multilayer stack 100includes the glass base 10 and the intermediate region 30 i of theplastic film 30.

In the example of FIG. 6, both the irradiation process with the lift-offlight and the delaminating process are carried out using thedelaminating apparatus 220 that includes the stage 212. The embodimentof the present disclosure is not limited to this example. Theirradiation process with the lift-off light may be carried out using alift-off light irradiation unit which includes a stage other than thestage 212, while the delaminating process is carried out using thedelaminating apparatus that includes the stage 212. In this case, afterirradiation with the lift-off light, it is necessary to transfer themultilayer stack 100 from the stage of the irradiation unit to the stage212. When the same stage is used for carrying out both the irradiationprocess with the lift-off light and the delaminating process, the stepof transferring the multilayer stack between the stages can be omitted.

As described above, in the present embodiment, the step of separatingthe multilayer stack 100 into the first portion 110 and the secondportion 120 is carried out while the stage 212 holds the second surface100 b of the multilayer stack 100 by suction. The essence of thisseparation step resides in that an unnecessary part of the multilayerstack 100 which is not a constituent of the OLED device 1000 separatestogether with the glass base 10 from the stage 212. In the presentembodiment, the cutting step illustrated in FIG. 2, i.e., the step ofcutting a part of the multilayer stack 100 exclusive of the glass base10 into the plurality of OLED devices 1000 and the remaining unnecessaryportions, is carried out before irradiation with the lift-off light.Carrying out the cutting step before the lift-off light irradiation stepis effective in realizing the separation illustrated in FIG. 5B and FIG.6.

In the present embodiment, the stage 212 plays an important role in theabove-described “separation”. Hereinafter, a configuration example ofthe stage 212 which can be suitably used in the present embodiment isdescribed.

Configuration Example 1 of Stage

FIG. 7 is a perspective view schematically showing a surface of thestage 212 in this example. FIG. 8 is a plan view schematically showingthe surface of the stage 212.

The stage 212 shown in the drawings includes a plurality of firstregions 300A which are to respectively face a plurality of OLED devices1000 (not shown) and a second region 300B which is to face theintermediate region 30 i of the plastic film 30. The suction in thefirst regions 300A is greater than the suction in the second region300B.

FIG. 9A is a schematic diagram enlargedly showing a portion in thevicinity of the boundary between the first region 300A and the secondregion 300B. FIG. 9B is a cross-sectional view taken along line B-B ofFIG. 9A. In this example, as shown in FIG. 9B, the stage 212 includes aporous front plate 222, a rear plate 224 which is parallel to the frontplate 222, a space 226 formed between these plates, and a suction sheet300 placed on the front plate 222. The space 226 is connected with asuction unit (not shown), such as a pump. During operation, the suctionunit makes the space 226 have a negative pressure, so that external airflows into the space 226 via a large number of voids of the porous frontplate 222 and openings (through holes 300H) of the suction sheet 300.Therefore, an object which is in contact with the suction sheet 300 issucked by the stage 212 and hence adhered by suction to the stage 212.

The porous front plate 222 can be made of various porous materials. Theporosity of the porous material is in the range of, for example, notless than 20% and not more than 60%. The average pore diameter is in therange of, for example, not less than 5 μm and not more than 600 μm. Anexample of the porous material is a sintered metallic or ceramic mass ora resin. The thickness of the porous material that forms the front plate222 is in the range of, for example, not less than 1 mm and not morethan 50 mm.

The suction sheet 300 has a plurality of through holes 300H as shown inFIG. 9A and FIG. 9B. The aperture ratio of the through holes 300H isdifferent between the first region 300A which is in contact with theOLED device 1000 and the second region 300B which is to face theintermediate region 30 i of the plastic film 30. The “aperture ratio” ofthe suction sheet 300 refers to the area proportion of a region(opening) in which the porous front plate 222 is exposed such that thesuction function can be performed in the surface of the stage 212.

The suction sheet 300 can be made of various materials such as, forexample, PET (polyethylene terephthalate), PVC (polyvinyl chloride), PP(polypropylene), fluoric resins (e.g., Polyflon), polyimide (PI), PC(polycarbonate), ABS resins. Alternatively, the suction sheet 300 may bemade of woven fabric, nonwoven fabric, a porous film, or the like. Thethickness of the suction sheet 300 can be, for example, about 0.05-3.0mm.

The surface of the porous front plate 222 can achieve generally uniformsucking force. When the suction sheet 300 is placed, the suction differsbetween the first region 300A and the second region 300B. A region ofthe surface of the front plate 222 which is covered with unopenedportions of the suction sheet 300 is incapable of sucking air and hencedoes not create suction. The suction sheet 300 can be used while it isadhered by suction to the porous front plate 222. The method of securingthe suction sheet 300 to the surface of the front plate 222 is notlimited to suction. The suction sheet 300 may be secured to the frontplate 222 or the stage 212 via an adhesive layer or a jig.

Using the suction sheet 300 in combination with an existing chuck stageeasily allows various designs of the multilayer stack 100. For example,when the shape, dimensions, number or arrangement pattern of the OLEDdevices 1000 is changed, the suction sheet is replaced by anothersuction sheet which is suitable to this change, whereby the in-planedistribution of the suction of the stage 212 can be easily changed. Inother words, it is only necessary to replace the suction sheet 300without changing the entirety of the stage 212.

In the present embodiment, the in-plane number density (hereinafter,simply referred to as “density”) of the through holes 300H in the firstregion 300A of the suction sheet 300 is higher than the density of thethrough holes 300H in the second region 300B. In other words, theaperture ratio of the first region 300A is higher than the apertureratio of the second region 300B. Therefore, the suction (sucking force)in the second region 300B is smaller than the suction in the firstregion 300A. The density of the through holes in the second region 300Bis about 0-50%, preferably about 0-30%, of the density of the throughholes 300H in the first region 300A. In one embodiment, the density ofthe through holes 300H in the second region 300B may be 0/cm².

The method of varying the suction between the first region 300A and thesecond region 300B is not limited to making difference in density of thethrough holes 300H in the suction sheet 300. By making difference insize and/or shape of the through holes 300H, difference can be made inaperture ratio, whereby the suction can be adjusted. Further, by makingthe thickness of the second region 300B of the suction sheet 300 smallerthan the thickness of the first region 300A, a gap may be formed betweenthe multilayer stack 100 and the second region 300B when the multilayerstack 100 is in contact with the first region 300A. Due to the presenceof such a gap, the suction in the second region 300B can be decreased.

By using the stage 212 which has the above-described configuration, inthe state shown in FIG. 5A, a plurality of flexible substrate regions 30d of the plastic film 30 which are in contact with the first regions300A of the stage 212 can respectively be adhered by suction to thefirst regions 300A of the stage 212. Meanwhile, the suction between theintermediate region 30 i of the plastic film 30 and the second region300B of the stage 212 is not strong. The intermediate region 30 i of theplastic film 30 is rather attached to the glass base 10. While theinterface between the intermediate region 30 i of the plastic film 30and the glass base 10 is irradiated with lift-off light, theintermediate region 30 i of the plastic film 30 can be kept attached tothe glass base 10 due to intermolecular forces, such as van der Waalsforce. Further, as previously described, when a part of the intermediateregion 30 i at an end of the plastic film 30 is secured to the glassbase 10 using a pin or jig, the entirety of the intermediate region 30 ican easily be kept on the glass base 10.

Further, in irradiating with lift-off light, the irradiation intensityof the lift-off light may be decreased for at least part of theintermediate region 30 i of the plastic film 30. If the irradiationintensity of the lift-off light is below a level required fordelamination, that part of the intermediate region 30 i of the plasticfilm 30 remains bound to the glass base 10. Thus, the intermediateregion 30 i of the plastic film 30 can easily be kept on the glass base10.

If the distance from the stage 212 to the glass base 10 is increasedwhile the stage 212 holds the second surface 100 b of the multilayerstack 100 by suction, the unnecessary portions of the multilayer stack100 can be separated together with the glass base 10 from the OLEDdevices 1000. The unnecessary portions of the multilayer stack 100 arenot adhered by suction to the second region 300B of the stage 212 andremain bound to the glass base 10.

In the configuration example described with reference to FIG. 9A andFIG. 9B, the shape and size of the first region 300A of the suctionsheet 300 which is in contact with the OLED device 1000 are identicalwith the shape and size of the OLED device 1000, although the embodimentof the present disclosure is not limited to this example. If the suctionin the first region 300A is sufficiently strong, the first region 300Aonly needs to face at least part of the OLED device 1000, rather thanthe entirety of the OLED device 1000.

FIG. 10 is a plan view showing a suction sheet 300 in anotherconfiguration example. The first regions 300A of the suction sheet 300can have an arbitrary shape and dimensions so long as the first regions300A hold by suction respective ones of the OLED devices 1000 includedin the multilayer stack 100 and do not come into contact with theintermediate region 30 i of the plastic film 30.

FIG. 11A is a schematic diagram enlargedly showing a portion in thevicinity of the boundary between the first region 212A and the secondregion 212B in another configuration example of the suction sheet 300.FIG. 11B is a cross-sectional view taken along line B-B of FIG. 11A. Inthis example, the first region 300A is defined by a large opening 300Pthrough which the surface 212S of the front plate 222 that is made of aporous material is exposed. Meanwhile, the second region 300B covers thesurface 212S of the front plate 222 that is made of a porous material,thereby performing the function of reducing the suction. In the exampleillustrated in the drawings, the second region 300B has the throughholes 300H, although the through holes 300H are not indispensable in thesecond region 300B.

Configuration Example 2 of Stage

FIG. 12A is a schematic diagram enlargedly showing a portion in thevicinity of the boundary between the first region 212A and the secondregion 212B in a stage 212 in which the front plate 222 is realized by aplate which has through holes, rather than a plate which is made of aporous material. FIG. 12B is a cross-sectional view taken along line B-Bof FIG. 12A.

In this example, the density or aperture ratio of through holes 300H inthe first region 212A is higher than the density or aperture ratio ofthrough holes 300H in the second region 212B. Thus, the suction in thesecond region 212B is smaller than the suction in the first region 212A.

As described herein, the stage 212 may have a plurality of regions ofdifferent suctions.

<Steps after Delaminating>

FIG. 13 is a perspective view showing the first portion 110 (OLEDdevices 1000) of the multilayer stack 100 adhered by suction to thestage 212 and the second portion 120 (the glass base 10 and objectsbound thereto) at a position distant from the stage 212. Unnecessaryportions of the multilayer stack 100 which are not constituents of theOLED devices 1000 are bound to the glass base 10.

FIG. 14 is a perspective view showing the first portion 110 of themultilayer stack 100 adhered by suction to the stage 212. The firstportion 110 of the multilayer stack 100 supported by the stage 212includes a plurality of OLED devices 1000 arrayed in rows and columns.In the example of FIG. 14, a part of the plastic film 30, specificallythe surface (delaminated surface) 30S of the flexible substrate regions30 d, is exposed.

FIG. 15 is a cross-sectional view showing that the stage 212 holds theOLED devices 1000 by suction. This cross section is parallel to the ZXplane. The direction of the Z-axis of FIG. 15 is opposite to thedirection of the Z-axis of FIG. 13 and FIG. 14.

Various processes can be sequentially or concurrently performed on theplurality of OLED devices 1000 which are in contact with the stage 212.

The “processes” to be performed on the OLED devices 1000 can includeattaching a dielectric and/or electrically-conductive film to each ofthe plurality of OLED devices 1000, cleaning or etching each of theplurality of OLED devices 1000, and mounting an optical part and/or anelectronic part to each of the plurality of OLED devices 1000.Specifically, a part such as, for example, a polarizer, encapsulationfilm, touchscreen, heat radiation sheet, electromagnetic shield, driverintegrated circuit, or the like, can be mounted to the flexiblesubstrate region 30 d of each of the OLED devices 1000. The sheet-likepart includes a functional film which can add an optical, electrical ormagnetic function to the OLED devices 1000.

The plurality of OLED devices 1000 are supported by the stage 212 suchthat the OLED devices 1000 are adhered by suction to the stage 212. Thevarious processes which are to be performed on each of the OLED devices1000 can be efficiently carried out.

The surface 30 s of the plastic film 30 delaminated from the glass base10 is active. Therefore, the surface 30 s may be covered with aprotection film or subjected to a surface treatment for conversion to ahydrophobic surface before various parts are mounted to the surface 30s.

FIG. 16 is a cross-sectional view schematically showing the OLED devices1000 detached from the stage 212 after the sheet-like part (functionalfilm) 60 is mounted to the OLED devices 1000.

According to the prior art, the plastic film is delaminated from theglass base before the OLED devices 1000 are divided from one another.Therefore, when a subsequent process is carried out, a large number ofOLED devices 1000 are bound to a single plastic film. Thus, it isdifficult to carry out an efficient process on each of the OLED devices1000. When the OLED devices 1000 are divided from one another after thesheet-like part is attached, a portion of the sheet-like part which ispresent in an intermediate region between adjoining two of the OLEDdevices 1000 is useless.

On the other hand, according to the embodiment of the presentdisclosure, a large number of OLED devices 1000 are still orderlyarrayed on the stage 212 after being delaminated from the glass base 10.Therefore, various processes can be efficiently performed on the OLEDdevices 1000 sequentially or concurrently.

After the step of separating the multilayer stack 100 into the firstportion 110 and the second portion 120, the step of adhering anotherprotection sheet (second protection sheet) 70 to the plurality of OLEDdevices 1000 which are in contact with the stage 212 may be furtherperformed as shown in FIG. 17. The second protection sheet 70 canperform the function of temporarily protecting the surface of theflexible substrate regions 30 d of the plastic film 30 delaminated fromthe glass base 10. The second protection sheet 70 can have the samelaminate structure as that of the previously-described protection sheet50. The protection sheet 50 can be referred to as “first protectionsheet 50”.

The second protection sheet 70 may be adhered to the plurality of OLEDdevices 1000 after various processes which have previously beendescribed are performed on the plurality of OLED devices 1000 which arein contact with the stage 212.

When suction of the OLED devices 1000 by the stage 212 is stopped afterthe second protection sheet 70 is adhered, the plurality of OLED devices1000 which are bound to the second protection sheet 70 can be detachedfrom the stage 212. Thereafter, the second protection sheet 70 canfunction as a carrier for the plurality of OLED devices 1000. This istransfer of the OLED devices 1000 from the stage 212 to the secondprotection sheet 70. Various processes may be sequentially orconcurrently performed on the plurality of OLED devices 1000 which arebound to the second protection sheet 70.

FIG. 18 is a cross-sectional view showing a carrier sheet 90 carrying aplurality of parts (functional films) 80 which are to be mounted to theplurality of OLED devices 1000. By moving this carrier sheet 90 in thedirection of arrow U, the respective parts 80 can be attached to theOLED devices 1000. The upper surface of the parts 80 has an adhesivelayer which is capable of strongly adhering to the OLED devices 1000.Meanwhile, the adhesion between the carrier sheet 90 and the parts 80 isrelatively weak. Using such a carrier sheet 90 enables a simultaneous“transfer” of the parts 80. Such a transfer is readily realized becausethe plurality of OLED devices 1000 are regularly arrayed on the stage212 while the OLED devices 1000 are supported by the stage 212.

Multilayer Stack

Hereinafter, the configuration of the multilayer stack 100 before thedividing of FIG. 2 is described in more detail.

First, see FIG. 19A. FIG. 19A is a cross-sectional view showing theglass base 10 with the plastic film 30 provided on the surface of theglass base 10. The glass base 10 is a supporting substrate forprocesses. The thickness of the glass base 10 can be, for example, about0.3-0.7 mm.

In the present embodiment, the plastic film 30 is a polyimide filmhaving a thickness of, for example, not less than 5 μm and not more than100 μm. The polyimide film can be formed from a polyamide acid, which isa precursor of polyimide, or a polyimide solution. The polyimide filmmay be formed by forming a polyamide acid film on the surface of theglass base 10 and then thermally imidizing the polyamide acid film.Alternatively, the polyimide film may be formed by forming, on thesurface of the glass base 10, a film from a polyimide solution which isprepared by melting a polyimide or dissolving a polyimide in an organicsolvent. The polyimide solution can be obtained by dissolving a knownpolyimide in an arbitrary organic solvent. The polyimide solution isapplied to the surface 30 s of the glass base 10 and then dried, wherebya polyimide film can be formed.

In the case of a bottom emission type flexible display, it is preferredthat the polyimide film realizes high transmittance over the entirerange of visible light. The transparency of the polyimide film can berepresented by, for example, the total light transmittance in accordancewith JIS K7105-1981. The total light transmittance can be set to notless than 80% or not less than 85%. On the other hand, in the case of atop emission type flexible display, it is not affected by thetransmittance.

The plastic film 30 may be a film which is made of a synthetic resinother than polyimide. Note that, however, in the embodiment of thepresent disclosure, the process of forming a thin film transistorincludes a heat treatment at, for example, not less than 350° C., andtherefore, the plastic film 30 is made of a material which will not bedeteriorated by this heat treatment.

The plastic film 30 may be a multilayer structure including a pluralityof synthetic resin layers. In one form of the present embodiment, indelaminating a flexible display structure from the glass base 10, laserlift-off is carried out such that the plastic film 30 is irradiated withultraviolet laser light transmitted through the glass base 10. A part ofthe plastic film 30 at the interface with the glass base 10 needs toabsorb the ultraviolet laser light and decompose (disappear).Alternatively, for example, a sacrificial layer which is to absorb laserlight of a certain wavelength band and produce a gas may be providedbetween the glass base 10 and the plastic film 30. In this case, theplastic film 30 can be easily delaminated from the glass base 10 byirradiating the sacrificial layer with the laser light. Providing thesacrificial layer also achieves the effect of suppressing generation ofashes.

<Polishing>

When there is an object (target) which is to be polished away, such asparticles or protuberances, on the surface 30 x of the plastic film 30,the target may be polished away using a polisher such that the surfacebecomes flat. Detection of a foreign object, such as particles, can berealized by, for example, processing of an image obtained by an imagesensor. After the polishing process, a planarization process may beperformed on the surface 30 x of the plastic film 30. The planarizationprocess includes the step of forming a film which improves the flatness(planarization film) on the surface 30 x of the plastic film 30. Theplanarization film does not need to be made of a resin.

<Lower Gas Barrier Film>

Then, a gas barrier film may be formed on the plastic film 30. The gasbarrier film can have various structures. Examples of the gas barrierfilm include a silicon oxide film and a silicon nitride film. Otherexamples of the gas barrier film can include a multilayer film includingan organic material layer and an inorganic material layer. This gasbarrier film may be referred to as “lower gas barrier film” so as to bedistinguishable from a gas barrier film covering the functional layerregions 20, which will be described later. The gas barrier film coveringthe functional layer regions 20 can be referred to as “upper gas barrierfilm”.

<Functional Layer Region>

Hereinafter, the process of forming the functional layer regions 20,including the TFT layer 20A and the OLED layer 20B, and the upper gasbarrier film 40 is described.

First, as shown in FIG. 19B, a plurality of functional layer regions 20are formed on a glass base 10. There is a plastic film 30 between theglass base 10 and the functional layer regions 20. The plastic film 30is bound to the glass base 10.

More specifically, the functional layer regions 20 include a TFT layer20A (lower layer) and an OLED layer 20B (upper layer). The TFT layer 20Aand the OLED layer 20B are sequentially formed by a known method. TheTFT layer 20A includes a circuit of a TFT array which realizes an activematrix. The OLED layer 20B includes an array of OLED elements, each ofwhich can be driven independently. The thickness of the TFT layer 20Ais, for example, 4 μm. The thickness of the OLED layer 20B is, forexample, 1 μm.

FIG. 20 is a basic equivalent circuit diagram of a sub-pixel in anorganic EL (Electro Luminescence) display. A single pixel of the displaycan consist of sub-pixels of different colors such as, for example, R(red), G (green), and B (blue). The example illustrated in FIG. 20includes a selection TFT element Tr1, a driving TFT element Tr2, astorage capacitor CH, and an OLED element EL. The selection TFT elementTr1 is connected with a data line DL and a selection line SL. The dataline DL is a line for transmitting data signals which define an image tobe displayed. The data line DL is electrically coupled with the gate ofthe driving TFT element Tr2 via the selection TFT element Tr1. Theselection line SL is a line for transmitting signals for controlling theON/OFF state of the selection TFT element Tr1. The driving TFT elementTr2 controls the state of the electrical connection between a power linePL and the OLED element EL. When the driving TFT element Tr2 is ON, anelectric current flows from the power line PL to a ground line GL viathe OLED element EL. This electric current allows the OLED element EL toemit light. Even when the selection TFT element Tr1 is OFF, the storagecapacitor CH maintains the ON state of the driving TFT element Tr2.

The TFT layer 20A includes a selection TFT element Tr1, a driving TFTelement Tr2, a data line DL, and a selection line SL. The OLED layer 20Bincludes an OLED element EL. Before formation of the OLED layer 20B, theupper surface of the TFT layer 20A is planarized by an interlayerinsulating film that covers the TFT array and various wires. A structurewhich supports the OLED layer 20B and which realizes active matrixdriving of the OLED layer 20B is referred to as “backplane”.

The circuit elements and part of the lines shown in FIG. 20 can beincluded in any of the TFT layer 20A and the OLED layer 20B. The linesshown in FIG. 20 are connected with an unshown driver circuit.

In the embodiment of the present disclosure, the TFT layer 20A and theOLED layer 20B can have various specific configurations. Theseconfigurations do not limit the present disclosure. The TFT elementincluded in the TFT layer 20A may have a bottom gate type configurationor may have a top gate type configuration. Emission by the OLED elementincluded in the OLED layer 20B may be of a bottom emission type or maybe of a top emission type. The specific configuration of the OLEDelement is also arbitrary.

The material of a semiconductor layer which is a constituent of the TFTelement includes, for example, crystalline silicon, amorphous silicon,and oxide semiconductor. In the embodiment of the present disclosure,part of the process of forming the TFT layer 20A includes a heattreatment step at 350° C. or higher for the purpose of improving theperformance of the TFT element.

<Upper Gas Barrier Film>

After formation of the above-described functional layer, the entirety ofthe functional layer regions 20 is covered with a gas barrier film(upper gas barrier film) 40 as shown in FIG. 19C. A typical example ofthe upper gas barrier film 40 is a multilayer film including aninorganic material layer and an organic material layer. Elements such asan adhesive film, another functional layer which is a constituent of atouchscreen, polarizers, etc., may be provided between the upper gasbarrier film 40 and the functional layer regions 20 or in a layeroverlying the upper gas barrier film 40. Formation of the upper gasbarrier film 40 can be realized by a Thin Film Encapsulation (TFE)technique. From the viewpoint of encapsulation reliability, the WVTR(Water Vapor Transmission Rate) of a thin film encapsulation structureis typically required to be not more than 1×10⁻⁴ g/m²/day. According tothe embodiment of the present disclosure, this criterion is met. Thethickness of the upper gas barrier film 40 is, for example, not morethan 2.0 μm.

FIG. 21 is a perspective view schematically showing the upper surfaceside of the multilayer stack 100 at a point in time when the upper gasbarrier film 40 is formed. A single multilayer stack 100 includes aplurality of OLED devices 1000 supported by the glass base 10. In theexample illustrated in FIG. 21, a single multilayer stack 100 includes alarger number of functional layer regions 20 than in the exampleillustrated in FIG. 1A. As previously described, the number offunctional layer regions 20 supported by a single glass base 10 isarbitrary.

<Protection Sheet>

Next, refer to FIG. 19D. As shown in FIG. 19D, a protection sheet 50 isadhered to the upper surface of the multilayer stack 100. The protectionsheet 50 can be made of a material such as, for example, polyethyleneterephthalate (PET), polyvinyl chloride (PVC), or the like. Aspreviously described, a typical example of the protection sheet 50 has alaminate structure which includes a layer of an applied mold-releasingagent at the surface. The thickness of the protection sheet 50 can be,for example, not less than 50 μm and not more than 200 μm.

After the thus-formed multilayer stack 100 is provided, the productionmethod of the present disclosure can be carried out using theabove-described production apparatus (delaminating apparatus 220).

INDUSTRIAL APPLICABILITY

An embodiment of the present invention provides a novel flexible OLEDdevice production method. A flexible OLED device is broadly applicableto smartphones, tablet computers, on-board displays, and small-, medium-and large-sized television sets.

REFERENCE SIGNS LIST

10 . . . glass base, 20 . . . functional layer region, 20A . . . TFTlayer, 20B . . . OLED layer, 30 . . . plastic film, 40 . . . gas barrierfilm, 50 . . . protection sheet, 100 . . . multilayer stack, 212 . . .stage, 220 . . . delaminating apparatus, 1000 . . . OLED device

1. A method for producing a flexible OLED device, comprising: providinga multilayer stack which has a first surface and a second surface, themultilayer stack including a glass base which defines the first surface,a plurality of functional layer regions each including a TFT layer andan OLED layer, a synthetic resin film provided between the glass baseand the plurality of functional layer regions and bound to the glassbase, the synthetic resin film including a plurality of flexiblesubstrate regions respectively supporting the plurality of functionallayer regions and an intermediate region surrounding the plurality offlexible substrate regions, and a protection sheet which covers theplurality of functional layer regions and which defines the secondsurface; dividing the intermediate region and respective ones of theplurality of flexible substrate regions of the synthetic resin film fromone another; irradiating an interface between the plurality of flexiblesubstrate regions of the synthetic resin film and the glass base withlaser light; and separating the multilayer stack into a first portionand a second portion by increasing a distance from a stage to the glassbase while the second surface of the multilayer stack is kept in contactwith the stage, wherein the first portion of the multilayer stackincludes a plurality of OLED devices which are in contact with thestage, and the plurality of OLED devices respectively include theplurality of functional layer regions and include the plurality offlexible substrate regions of the synthetic resin film, and the secondportion of the multilayer stack includes the glass base and theintermediate region of the synthetic resin film, the method furthercomprising, after separating the multilayer stack into the first portionand the second portion, sequentially or concurrently performing aprocess on the plurality of OLED devices which are in contact with thestage, wherein the process includes at least one of: attaching adielectric and/or electrically-conductive film to each of the pluralityof OLED devices; cleaning or etching each of the plurality of OLEDdevices; and mounting an optical part and/or an electronic part to eachof the plurality of OLED devices.
 2. The method of claim 1, whereinseparating the multilayer stack into the first portion and the secondportion is carried out while the stage holds the second surface of themultilayer stack.
 3. The method of claim 2, wherein irradiating theinterface between the plurality of flexible substrate regions of thesynthetic resin film and the glass base with the laser light is carriedout while the stage holds the second surface of the multilayer stack. 4.The method of claim 1 further comprising, after separating themultilayer stack into the first portion and the second portion, adheringanother protection sheet to the plurality of OLED devices which are incontact with the stage.
 5. A method for producing a flexible OLEDdevice, comprising: providing a multilayer stack which has a firstsurface and a second surface, the multilayer stack including a glassbase which defines the first surface, a plurality of functional layerregions each including a TFT layer and an OLED layer, a synthetic resinfilm provided between the glass base and the plurality of functionallayer regions and bound to the glass base, the synthetic resin filmincluding a plurality of flexible substrate regions respectivelysupporting the plurality of functional layer regions and an intermediateregion surrounding the plurality of flexible substrate regions, and aprotection sheet which covers the plurality of functional layer regionsand which defines the second surface; dividing the intermediate regionand respective ones of the plurality of flexible substrate regions ofthe synthetic resin film from one another; irradiating an interfacebetween the plurality of flexible substrate regions of the syntheticresin film and the glass base with laser light; and separating themultilayer stack into a first portion and a second portion by increasinga distance from a stage to the glass base while the second surface ofthe multilayer stack is kept in contact with the stage, wherein thefirst portion of the multilayer stack includes a plurality of OLEDdevices which are in contact with the stage, and the plurality of OLEDdevices respectively include the plurality of functional layer regionsand include the plurality of flexible substrate regions of the syntheticresin film, and the second portion of the multilayer stack includes theglass base and the intermediate region of the synthetic resin film, themethod further comprising, after separating the multilayer stack intothe first portion and the second portion, adhering another protectionsheet to the plurality of OLED devices which are in contact with thestage.
 6. The method of claim 5 further comprising detaching from thestage the plurality of OLED devices which are bound to the anotherprotection sheet.
 7. The method of claim 6 further comprisingsequentially or concurrently performing a process on the plurality ofOLED devices which are bound to the another protection sheet, whereinthe process includes at least one of: attaching a dielectric and/orelectrically-conductive film to each of the plurality of OLED devices;cleaning or etching each of the plurality of OLED devices; and mountingan optical part and/or an electronic part to each of the plurality ofOLED devices.
 8. An apparatus for producing a flexible OLED device,comprising: a stage for supporting a multilayer stack which has a firstsurface and a second surface, the multilayer stack including a glassbase which defines the first surface, a plurality of functional layerregions each including a TFT layer and an OLED layer, a synthetic resinfilm provided between the glass base and the plurality of functionallayer regions and bound to the glass base, the synthetic resin filmincluding a plurality of flexible substrate regions respectivelysupporting the plurality of functional layer regions and an intermediateregion surrounding the plurality of flexible substrate regions, and aprotection sheet which covers the plurality of functional layer regionsand which defines the second surface, the intermediate region andrespective ones of the plurality of flexible substrate regions of thesynthetic resin film being divided from one another; a lift-off lightirradiation unit for irradiating with laser light an interface betweenthe plurality of flexible substrate regions of the synthetic resin filmand the glass base in the multilayer stack supported by the stage, thelift-off light irradiation unit configured to decrease an irradiationintensity of the laser light for at least part of the intermediateregion such that the irradiation intensity of the laser light is below alevel required for delamination; and an actuator for increasing adistance from the stage to the glass base while the stage holds thesecond surface of the multilayer stack by suction, thereby separatingthe multilayer stack into a first portion and a second portion, whereinthe first portion of the multilayer stack includes a plurality of OLEDdevices adhered by suction to the stage, and the plurality of OLEDdevices respectively include the plurality of functional layer regionsand include the plurality of flexible substrate regions of the syntheticresin film, and the second portion of the multilayer stack includes theglass base and the intermediate region of the synthetic resin film, thestage includes a porous plate, and a suction sheet placed on the porousplate, the suction sheet having a plurality of openings, and the suctionsheet includes a first region which is to be in contact with theplurality of OLED devices and a second region which is to face theintermediate region of the synthetic resin film, an aperture ratio ofthe first region being higher than an aperture ratio of the secondregion.
 9. An apparatus for producing a flexible OLED device,comprising: a stage for supporting a multilayer stack which has a firstsurface and a second surface, the multilayer stack including a glassbase which defines the first surface, a plurality of functional layerregions each including a TFT layer and an OLED layer, a synthetic resinfilm provided between the glass base and the plurality of functionallayer regions and bound to the glass base, the synthetic resin filmincluding a plurality of flexible substrate regions respectivelysupporting the plurality of functional layer regions and an intermediateregion surrounding the plurality of flexible substrate regions, and aprotection sheet which covers the plurality of functional layer regionsand which defines the second surface, the intermediate region andrespective ones of the plurality of flexible substrate regions of thesynthetic resin film being divided from one another; a lift-off lightirradiation unit for irradiating with laser light an interface betweenthe plurality of flexible substrate regions of the synthetic resin filmand the glass base in the multilayer stack supported by the stage, thelift-off light irradiation unit configured to decrease an irradiationintensity of the laser light for at least part of the intermediateregion such that the irradiation intensity of the laser light is below alevel required for delamination; and an actuator for increasing adistance from the stage to the glass base while the stage holds thesecond surface of the multilayer stack by suction, thereby separatingthe multilayer stack into a first portion and a second portion, whereinthe first portion of the multilayer stack includes a plurality of OLEDdevices adhered by suction to the stage, and the plurality of OLEDdevices respectively include the plurality of functional layer regionsand include the plurality of flexible substrate regions of the syntheticresin film, and the second portion of the multilayer stack includes theglass base and the intermediate region of the synthetic resin film,wherein a surface of the stage includes a first region which is to facethe plurality of OLED devices and a second region which is to face theintermediate region of the synthetic resin film, and suction in thefirst region is greater than suction in the second region.
 10. A suctionsheet for use in the apparatus of claim 8, comprising: a first regionwhich is to be in contact with the plurality of OLED devices; and asecond region which is to face the intermediate region of the syntheticresin film, wherein an aperture ratio of the first region is higher thanan aperture ratio of the second region.